1. Field of the Invention
The invention relates generally to thermal electric generation, and in particular to generating electricity from heat produced by the combustion of hydrocarbon fuels.
2. Background of the Invention
Currently, electric generators produce electricity by converting one form of energy into electricity. For example, metal hydride fuel cells, when mixed with water, produce hydrogen from an exothermic reaction. This hydrogen is then mixed with other chemicals to generate electricity. Another type of generator uses energy from fossil fuel to rotate a turbine. The mechanical rotation of the turbine generates electricity.
In both types of electric generators described above, the generators produce a large amount of heat. The temperature inside of the generator can reach as high as 600 degrees K. This heat is not used to generate electricity. Instead, it is lost to the environment as waste. This loss is not a problem in conventional generators because there is no real advantage in converting the excess heat from a 250-Watt generator into a few extra watts of power. Also, the fuel supply for traditional electric generators is relatively inexpensive and readily available. For example, fossil fuel can be easily bought at a reasonable price across the country. Therefore, it is not necessary to use this excess heat to generate electricity, and it is lost to the environment as waste.
However, people who use electric generators in a remote environment must carry their own fuel supply with them, because fuel is not readily available in this remote environment. Supplying additional fuel to a person in a remote environment is very expensive. If the person is lost in the woods, or is stranded at sea, supplying additional fuel becomes impossible.
There are numerous uses for electric generators in remote environments. These uses include providing electricity to electronic survival equipment in lifeboats, or to rescuers in a dense forest; or providing electricity for special industrial uses, such as remote exploration for oil. One of the most important uses for portable electric generators capable of being carried by a person is for national defense. Soldiers in the field need electric generators to provide electricity to their radios and electronic equipment.
The microturbine generators and fuel cell generators used in these remote environments reach temperatures above 300 degrees F. Losing energy from the limited fuel supply as wasted heat is significant, because the fuel supply is very scarce. Between 6 to 30 percent of the energy from the total fuel supply is converted into excess heat, which is then lost to the environment.
For example, the portable electric generators used by soldiers in the field generate 360 to 720 Watt-hours of electricity per day. The heat produced by these generators is a source of energy that can be harnessed to produce 1 or 2 Watts of electricity per hour, which is up to 48 Watt-hours of electricity per day. Thus, the limited fuel supply can be conserved if the heat produced by the generators is not wasted. The batteries that are recharged by these generators can last 20 or 30 percent longer. This increase in electric power can mean the difference between life and death to soldier at the front line, or to a person stranded in a lifeboat.
Therefore, there is a strong need, in a remote environment, to convert excess heat produced by electric generators into electric power. The present invention meets this need by using thermal electric generators to convert excess heat from electric generators into electric power. The present invention has several advantages over conventional portable generators. The present invention conserves the fuel used by the generator, extends the life of batteries that are recharged by the generator, and provides more electricity to a person in a remote environment than conventional portable generators.
The present invention also has several advantages over traditional thermal electric generators. Traditionally, thermal electric generators are large stand-alone devices, which, by themselves, provide electric power. A disadvantage, however, is that these generators are too large and use too much fuel to be carried by people into remote environments.
Smaller thermal electric generators, capable of generating 1 or 2 Watts of electricity an hour, can be used, together-with other types of electric generators, to provide an adequate supply of electricity in a remote environment. When thermal electric generators are attached to the high temperature areas of other types of electric generators, the result is an electric generator that effectively uses the limited fuel supply that is carried by a person into a remote environment.
The invention is an electric generator comprising a portable heat generator and a thermal electric co-generator. The co-generator converts heat produced by the portable heat generator into electricity. In one embodiment of the present invention, the portable generator is a microturbine. In another embodiment, the portable generator is a fuel cell. In a further embodiment, the heat generator is the barrel of a weapon. In a further embodiment, the thermal electric generator also functions as a sensor for measuring the temperature of the heat generator.